The mouse E beta 2 gene: a class II MHC beta gene with limited intraspecies polymorphism and an unusual pattern of transcription.

Analysis of genomic clones containing the E beta 2 region from the mouse major histocompatibility complex (MHC) reveals a gene that is similar to conventional class II beta genes in its overall organization and sequence but unusual in that it shows limited intraspecies allelic polymorphism. Like the conventional class II beta genes, the E beta 2 gene is transcriptionally active in a variety of B lymphoid cells. However, its transcripts consist of multiple polyadenylated species from 1.8 to 3.6 kb in size which are present at only approximately 1/20 the level of E beta 1 mRNA in the same cells. In addition, unlike other class II genes, E beta 2 transcription is not induced by gamma-interferon treatment of macrophage/monocyte tumor lines. These distinctive features suggest that the E beta 2 gene product may have a unique functional role, different from that of previously studied class II proteins.